Constrained Tetramic Acids, Homostreptopyrrolidine, and their Analogues Based on Unusual Intramolecular Wittig Olefination with Phosphorus Ylides

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Silver‐Catalyzed Diastereoselective Synthesis of Spirocyclic Pyrrolidine‐Lactones by 1,3‐Dipolar Cycloaddition

The preparation of two enantiomerically enriched amino lactones as chiral starting substrates for asymmetric 1,3‐dipolar cycloadditions is described. They act as precursors of the chiral imino lactones, which form in situ the corresponding azomethine ylides. They react with electrophilic alkenes under silver catalysis to afford spirolactone‐pyrrolidines products. The sequential method consisting in one‐pot imine formation → cycloaddition is optimized and compared with the multicomponent process. The scope of the reaction is studied as well as the stereochemical outcomes and the mechanistic details using DFT calculations and X‐ray diffraction analysis.We gratefully acknowledge financial support from the Spanish Ministerio de Economía y Competitividad (MINECO) Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (pro-jects CTQ2013-43446-P, CTQ2014-51912-REDC, CTQ2016-76782-P, CTQ2016-81797-REDC and CTQ2016-76155-R), the Generalitat Valenciana (PROMETEOII/2014/017), the University of Alicante. This research was also supported by the Slovak Research and Development Agency under contract VEGA 1/0489/19

Conformationally constrained homophenylalanine derivatives. Synthesis of the substituted 2,3,4,5-tetrahydro-1H-2-benzazepine-3-carboxylic acids

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CIAT with simultaneous epimerization at two stereocenters. Synthesis of substituted β-methyl-α-homophenylalanines

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Toward the improvement of the tandem halide displacement/amide coupling spiro-cyclization as a new route to γ-lactam and pyrroloisoquinoline templates

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Antibacterial Electrospun Polycaprolactone Nanofibers Reinforced by Halloysite Nanotubes for Tissue Engineering

Due to its slow degradation rate, polycaprolactone (PCL) is frequently used in biomedical applications. This study deals with the development of antibacterial nanofibers based on PCL and halloysite nanotubes (HNTs). Thanks to a combination with HNTs, the prepared nanofibers can be used as low-cost nanocontainers for the encapsulation of a wide variety of substances, including drugs, enzymes, and DNA. In our work, HNTs were used as a nanocarrier for erythromycin (ERY) as a model antibacterial active compound with a wide range of antibacterial activity. Nanofibers based on PCL and HNT/ERY were prepared by electrospinning. The antibacterial activity was evaluated as a sterile zone of inhibition around the PCL nanofibers containing 7.0 wt.% HNT/ERY. The morphology was observed with SEM and TEM. The efficiency of HNT/ERY loading was evaluated with thermogravimetric analysis. It was found that the nanofibers exhibited outstanding antibacterial properties and inhibited both Gram- (Escherichia coli) and Gram+ (Staphylococcus aureus) bacteria. Moreover, a significant enhancement of mechanical properties was achieved. The potential uses of antibacterial, environmentally friendly, nontoxic, biodegradable PCL/HNT/ERY nanofiber materials are mainly in tissue engineering, wound healing, the prevention of bacterial infections, and other biomedical applications

Asymmetric Synthesis and Binding Study of New Long-Chain HPA-12 Analogues as Potent Ligands of the Ceramide Transfer Protein CERT

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